Question: Which wireless standard should I use?
The most popular wireless standards are 802.11ac and 802.11n, however I would recommend 802.11ac since it’s a mature technology that provides much faster bandwidth (up to 1.3Gbps) if you compare to 802.11n and the price is reasonable nowadays. If your wireless router supports 802.11ac, then you can easily connect laptop or mobile device with 802.11ac support to it easily to join high speed network access.
However please note that 802.11ac works in 5 GHz band only but still it is backward compatible with 802.11n, 802.11g, 802.11b and 802.11a wireless standards, therefore you can use it for wireless devices in 2.4 GHz with 802.11n wireless standard. This means you don't have to worry if you still got laptop or desktop that supports older wireless standards only.
The other consideration is that higher bands are faster but lower bands travel further, that means the coverage of 5 GHz band network is smaller than 2.4 GHz band network.
Other than latest 802.11ac wireless standard, IEEE has been developing 802.11ax that can provide bandwidth support 4x to 10x faster than existing wireless network for many years, and is expected to be finalized sometime in late 2019 or early 2020. It works in 2.4GHz and 5GHz bands and one of the other benefit of 802.11ax is to allow many devices connecting to wireless network without causing serious congestion issue.
802.11ax is designed specifically for high-density public environments, such as hotels, airports, stadiums and other public areas, therefore should be more than enough to fulfill home wireless network needs when it's released later. Although still the 802.11ax standard is not finalized with ratification, some vendors have started to manufacture and market 802.11ax wireless router but in high selling price, therefore I would advise you to only consider 802.11ax wireless router after the finalization of 802.11ax standard unless you really need it.
Note: Each wireless standard typically will be valid for 10 years before having another newer wireless standard.